Internal-combustion engine



1,633 921 June 28, 1927. E. R BURTNETT INTERNAL COMBUSTION ENGINE Filed Oct. 26, 1922 2 Sheets-Sheet l 1,633,921 n I E. R. BURTNETT I INTERNAL COMBUSTION ENGINE Filed Oct. 26, 1922 2 Sheets-Sheet 2 ,l der zjazww Patented lane 28, .1927.

UNITED STATES PATENT OFFICE.

EVERETT IR. BURTNETT, 015 LOS ANGELES, CALHORN'IA, ASSIGNOR, BY DIRECT AND 1 MESNE ASSIGNMENTS, TO THE AUTOMOTIVE VALVES 00., OF LOS ANGELES, CALI- FORNIA (A VOLUNTARY TRUST).

INTERNAL-COMBUSTION ENGINE.

Application filed October 26, 1922. Serial No. 596,958.

My invention relates generally to internal combustion engines and more particularly to a two stroke cycle, three cylinder engine unit, the principal object of my invention being to provide an engine having two power pistons operating within a common combustion and expansion chamber, the angularity of the cranks of the two pistons with respect to each other, being such as to permit mainto tenance of maximum compression for the period of time required to enable the piston having the crank in advance of the other, to move out of the dead center toggle before ignition occurs. This crank angle effect to 5 the rise in pressure by combustion, is obtained in conventional engines, by retarding the spark, and which action is attended by the disadvantage of the compression falling below maximum before ignition takes place, such result proportionately decreasing the combustion pressure and power obtained.

A further object of my invention is to provide a valveless engine wherein Stratification of the inducted charge is effected and which charge, when ignited, compounds or has double expansive effect upon the working or power pistons.

Further objects of my invention are to generally improve upon and simplify the construction of the existing types of two stroke cycle engines and to provide an engine that may be easily and cheaply produced and which-will have the desirable advantages of a relatively high power development with minimum fuel consumption.

With the foregoing and other objects in view, my invention consists in certain novelfeatures of construct1on and arrangement of parts that will behereinafter more fully described and claimed and illustrated in the accompanying drawings, in which:

Fig. 1 is a vertical section taken lengthwise through the center of an'engine of my improved construction. a

Fig. 2 is a horizontal section taken on the line 22 of Fig. 1.

Fig. 3 is an end elevational view of the engine, with dotted lines showing the positions of the crank arms on the crank shaft. Fig. 4 is a horizontal section taken on the line 44: of Fig. 1".- it

Referring by numerals to the accompanying drawings which illustrate a practical embodiment of my invention, 10 designates a cylinder block, preferably of integral construction and in which are formed three chambers 11, 12 and 13.

The upper ends of these chambers are closed by an integrally formed head block 14,- in the under side of which is. formed a shallow recess or chamber 15 that establishes communication between the chambers 11 and 12. Block 14 and the walls surrounding the chambers 11, 12 and 1.3 are provided with communicating chambers 16, throu h which cooling a port 19 with the upper end of chamber 13 L and its lower end communicating through a relatively long horizontally disposed port 20,

with the intermediate portion of chamber 12.

Formed through the wall that surrounds chamber 13 and at an intermediate point between its ends is a port or a series of ports 21, that serve to admit gaseous fuel fromv a suitable source of supply to the compression chamber 13.

- The ports 17 20 and 21 occupy substantially the same horizontal plane and their location between the ends of the chambers 11, 12 and 13 is that they are wholly, uncovered, only when the pistons that operate within said chambers are at their low centers, or at the outer ends of their strokes.

Seated in block 14, preferably at a point between the axis of chamber 12 and the ada jacent side of chamber 13 is a spark plugl22, the inner ends of the electrodes 0 w project into chamber 15.

ich

-Arranged for reciprocatory movement within the chambers 11, 12 andfl13 are respectively, pistons 23, 24 and 25.

Formed integral with block 10 1s a depending skirt portion 26 that serves as a crank case and journalled in suitable bearings in the ends thereof is a crank shaft 27,

having three cranks 28, 29 and 30 that are I respectively positioned beneath chambers 11, 12 and 13.

Pistons 23, 24 and 25 are connected respectively to cranks 28, 29 and 30 by suitable connecting rods 31, 32 and 33.

The crank angularity between cranks 28 and 29 is approximately 60 degrees, while crank 30 is diametrically opposite or 180 degrees from crank 29 and approximately 120 degrees from crank 28 (see'Fig. 3).

In my improved engine, it will be noted that chambers 11 and 12 connected by chamber 15, constitute a common combustion or expansive chamber and therefore pistons '23 and 24 are both instrumental in transmitting motion and power to crank shaft 27, the latter being common to all cylinders of the engine unit and having a separate crank throw for each of the three pistons.

The ports 17 and 20 are located so as to be uncovered for registration with the piston displacement chamber at the outer ends of the ,piston stroke or as the power pistons pass the crank end centers. As piston 25 passes low center, inlet ports 21 are uncovered, thereby admitting to com ression chamber 13, a charge of gaseous fue On the succeeding upward stroke of piston 25, this charge of gaseous fuel is compressed in the upper portion of chamber 13 and in duct 18.

As piston 24 passes low center, port 20 is uncovered thereby admitting the compressed charge of gaseous fuel into chamber 12.

In my improved engine it is essential that the exhaust ports be closed before the transfer of compressed gases begins through duct 18 in order to retain a maximum of residual volume in the chambers 11 and 12 at atmospheric pressure and to prevent volume circulation through said chambers during fuel mixture induction and which latter action, if permitted would destroy the desired Stratification effect. Due to the relative positions of cranks 28 and 29, piston 23 travels in advance of piston 24 so that the exhaust ports close as the gaseous fuel inlet port 20 opens.

During the upward travel of pistons 23 and 24, the residual products of combustion and the admitted charge of gaseous fuel are compressed in the upper portions of chambers 11 and 12 and connecting chamber 15 and, as the gaseous fuel charge was admitted to chamber 12, the greater portion of the entire volume of said charge will be compressed in a stratum within the upper por tion of chamber 12 and within the right hand portion of chamber or recess 15.

As piston 24 passes high center or immediately thereafter, a spark is produced between the terminals of the electrodes of plug 22, thereby igniting the compressed gaseous fuel charge and the force of the resultant expansion will be directed against the heads of both pistons to drive the same downward on the power stroke.

At the time of ignition of the compressed charge as just described, piston 23 is approximately 60 degrees in crank throw in advance of piston 24 so that by the time the flame propagation has passed through the entire volume of the compressed charge, piston 23 is well out of toggle and piston 24 is past high center, so that, following complete combustion of the gaseous fuel, the force of the expansion within the connected chambers 11 and 12 will be directed against the heads of both pistons.

Obviously by thus compounding the expansive power within the chambers 11 and 12 and applying the same to the pistons while the cranks thereof are out of toggle and moving through their are of greatest transmission to the crank shaft and adds materially to the power production in an engine of given size with a -minimum of fuel consumption.

As piston 23 approaches low center, exhaust ports 17 are uncovered, thereby permitting the pressure within the connected chambers to drop to atmospheric pressure and an instant later and after the ports 17 are closed, fuel inlet port 20 will be opened to admit a fresh charge of compressed gaseous fuel as hereinbefore described.

Thus it will seem that I have produced a two stroke cycle engine that is devoid of.

valves, and in which, charge Stratification and compounding of the expansive force of the ignited charge are utilized for the very economical production of power.

Obviously the details of construction of my improved engine may be varied in size and form without departing from the spirit of the invention, the scope of which is set forth in the appended claim.

I claim as my invention:

In a two stroke cycle power develo ment and charge induction unit, a series 0 three cylinders arranged in a row, each cylinder having a straight diameterbore, the cylinder at one end of the row functioning as a pump cylinder, the head or inner ends of the chambers in the other two cylinders being connected by a common compression and combustion clearance chamber and functioning as combustion chambers, a transfer duct leading from the head end of the chamber in the pumping cylinder to the intermediate portion of the adjacent combustion chamber, there being exhaust ports formed through the intermediate portion of the wall surrounding the other one of the combustion chambers, pistons arranged for reciprocatory movement within the chambers of the three cylinders, a crank shaft having three crank pins to which the three pistons are respectively connected by separate connections, the pins of said crank shaft to which the piston in the pumping the direction of crank rotation, from the pin cylinder and the piston in the immediately, .to which the piston in the pumping cham-. ad'acent combustion cylinder are connected her is connected. being arranged 180 apart and the crank In testimony 'whereof I have signed my 5 pin to which the piston that operates within name to this specification.

the combustion chamber having the exhaust ports, being disposed 120 to" the rear, in EVERETT R. BURTNETT. 

